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Wormholes in Shape Space: Tracking Through Discontinuous Changes in Shape
Tony Heap and David Hogg


Author(s):
Abstract:
Existing object tracking algorithms generally use some form of local optimisation, assuming that an object's position and shape change smoothly over time. In some situations this assumption is not valid: the trackable shape of an object may change discontinuously, for example if it is the 2D silhouette of a 3D object. In this paper we propose a novel method for modelling temporal shape discontinuities explicitly. Allowable shapes are represented as a union of (learned) bounded regions within a shape space. Discontinuous shape changes are described in terms of transitions between these regions. Transition probabilities are learned from training sequences and stored in a Markov model. In this way we can create `wormholes' in shape space. Tracking with such models is via an adaptation of the CONDENSATION algorithm.

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International Conference on Computer Vision '98
Bombay, India.
CDROM version produced at I I T, Bombay..